class JustCounter:
    __secretCount = 0  # 私有变量
    publicCount = 0  # 公开变量

    def count(self): # 公开方法
        self.__secretCount += 1
        self.publicCount += 1
        print(self.__secretCount)

justCounter = JustCounter()
justCounter.count()  # 1
justCounter.count()  # 2

print(justCounter.publicCount)  # 2
print(justCounter._JustCounter__secretCount)
print(justCounter.__secretCount)  # AttributeError: 'JustCounter' object has no attribute '__secretCount'
